1. Field of the Invention
The present invention relates to a magnetic tape running state and tape run amount display device which usually displays the running direction, the running speed, and the amount of run of a magnetic tape.
2. Description of the Prior Art
In a tape recorder, a magnetic tape is run in a first or forward direction at a constant speed for recording and playing, and is run in a second or reverse direction at a higher speed for rewinding. In these tape transport operations, the tape running state is important for proper operation and should be carefully monitored at all times. Moreover, a counter is typically provided in a conventional tape recorder to indicate the amount of run of the magnetic tape. The amount of run of the magnetic tape, or the amount of the remaining length of tape can be determined by reading the counter.
With respect to tape running direction and speed, a conventional tape recorder of the cassette tape type often provides a visual indication of the direction and speed through the use of openings coincident with the small transparent window of the cassette housing. However, the transparent window cannot be observed visually unless the user can see the window, which is often impossible when the user is removed from the tape recorder.
One conventional approach for providing a visual indication of the running direction and speed as well as the amount of run of the magnetic tape is the mechanical digital counter, which is coupled to the open reel or cassette reel and which moves a counter element in accordance with the rotation of the open or cassette reel. A numerical scale on the counter element provides a visual indication of the amount of run or the remaining amount of magnetic tape. The running direction and speed is provided by the direction and speed of movement of the counter element.
Such a conventional mechanical digital counter, however, exhibits several major deficiencies. Because the digital counter must be mechanically coupled to the open reel or cassette reel, the position of the counter in the tape recorder is limited, and the amount of required space especially along the surface of the tape recorder housing is great. In addition, because the operation of the counter is slow and intermittent, it is difficult to determine quickly and accurately the direction and speed of the tape.